Using the EXECIO Command

EXECIO reads information from a data set with either the DISKR or DISKRU operands. Using these operands, you can also open a data set without reading its records. Refer to Reading Information from a Data Set for more information about the DISKR and DISKRU operands. EXECIO writes information to a data set with the DISKW operand. Using this operand, you can also open a data set without writing records or empty an existing data set. Refer to Writing Information to a Data Set for more information on the DISKW operand.

Before an exec can use the EXECIO command to read from or write to a data set, the data set must meet the following requirements. An I/O data set must be:

Either sequential or a single member of a PDS.
Previously allocated with the appropriate attributes for its specific purpose. Some examples of the various uses of EXECIO and the type of data set allocation appropriate for these uses are shown in and after Copying Information From One Data Set to Another.

If you use EXECIO to read information from a data set and to the data stack, the information can be stored in FIFO or LIFO order on the data stack. FIFO is the default. If you use EXECIO to read information from a data set and to a list of variables, the first data set line is stored in variable1, the second data set line is stored in variable2, and so on. Data read into a list of variables can be accessed randomly. After the information is in the data stack or in a list of variables, the exec can test it, copy it to another data set, or update it before returning it to the original data set.